JPS62285961A - Paint composition for partial repair - Google Patents

Abstract

PURPOSE:To obtain a paint for partial repair, which does not exhibit any black stain phenomenon caused by the deposition and stabilization of staining components in an environment, containing a film-forming resin component and kerosine. CONSTITUTION:A paint compsn. contains a film-forming resin component and 30-150wt% (per 100wt% resin component on a solid basis) kerosine. As the film-forming resin component, those conventionally used as paints such as mixtures of at least one resin selected from among a polyester resin, an alkyd resin, an acrylic resin and an epoxy resin and a curing agent such as an amino resin or an isocyanate resin can be used. When the amount of kerosine is less than 30wt% based on a solid basis of the resin, a poor appearance results, while when the amount exceeds 150wt%, the effect of filling fine pores is lowered and stain components in an environment are deposited and stabilized to thereby form black stains.

Description

Detailed Description of the Invention 3. Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a paint composition for partial repair used for partial repair of a coating film applied to a steel plate such as an automobile body.

(Conventional technology) The conventional partial repair method involves scraping away the defective part of the paint film with sandpaper, applying repair paint to the deep dents formed there with a brush or air spray, and then applying the repair paint to the repaired area. The surface is smoothed to the same level as the surrounding paint surface, and is rubbed with a compound to prevent any repair marks from remaining, and then finished with a coat of glossy wax.

(Problems to be Solved by the Invention) However, in such conventional partial repair methods, the resin layer on the surface of the paint film is polished off during the polishing process using sandpaper, etc., resulting in countless scratches on the pigment dispersion layer. occurs, and the smoothness of the normal surface cannot be obtained even after the finishing process. Such grooves or scratches in the surface layer of the polished surface adhere and stabilize minute dirt components in the environment, making the repaired area stand out in a pale black color. This phenomenon is called "black stain" and is particularly noticeable on white color, and occurs several days to several months after the repaired surface is placed in an outdoor environment, which significantly impairs the initial marketability. There was a point.

(Means for solving the problems) The present invention focuses on the above-mentioned conventional problems, and after the grinding process,
The above-mentioned problems were solved by developing a coating composition containing a film-forming resin component that is applied with flannel cloth, etc., and 30 to 150% by weight of kerosene based on the solid content of the resin component of 100% by weight. It is.

In the present invention, the coating film forming resin component is polyester resin,
A resin component commonly used as a paint is used, such as a mixture of at least one resin selected from the group consisting of alkyd resins, acrylic resins, and epoxy resins, and an amine resin or incyanate-containing resin as a curing agent. be able to.

In the partial repair paint of the present invention, kerosene is added to the coating film-forming resin component at 3% by weight based on the solid content of the resin component.
It is contained in a proportion of 0 to 150% by weight.

Although other solvents (eg, esters, aromatics, etc.) can be used for the purpose of dissolving or diluting the resin, it is necessary to add kerosene within the above-mentioned amount range. This is because the coating composition of the present invention is used in the same way as when applying wax with flannel cloth, etc.
If kerosene is less than 30% by weight based on the resin solid content, it will cause poor appearance (If!), and if it exceeds 150% by weight, the filling effect in fine pores will be reduced and dirt components in the environment will be removed. This is because it adheres and stabilizes to form a "black stain." Further, kerosene is used in waxes, abrasives, etc., and is preferable because it has a slow evaporation rate, has a low dissolving power in coating films, and does not cause swelling.

Furthermore, in the present invention, in addition to the above-mentioned kerosene, a nonionic surfactant is contained in a proportion of 0 to 10% by weight based on the solid content of the resin. This nonionic surfactant is used to improve workability and to mix kerosene with resins or solvents, but it has lower foaming power and less compatibility with solvents than cationic and anionic surfactants. It also has good water resistance because it does not undergo ionic dissociation. The amount of this nonionic surfactant added varies depending on the amount of kerosene; it cannot be generally specified, but it is 10% based on the resin solid content.
If it exceeds this, water resistance etc. will deteriorate. However, a better repaired surface can be obtained by adding it than by not adding it.

(Effects of the Invention) As described above, the paint composition for partial repair of the present invention contains a paint-forming resin component and 30 to 150% by weight of kerosene based on 100% by weight of the solid content of this resin component. It has workability that is comparable to that of wax, and when applied, it forms a coating film, so it does not deteriorate due to heat, water, light, etc. as well as ordinary coatings, so it is not temporary like wax. It is not a temporary effect, but can maintain its effect for a long period of time. Also, since the coating film Tq (glass transition point) is over 80℃, it does not become sticky even when the temperature rises in the summer, such as on automobile bodies. Excellent partial repair of the paint film can be achieved without causing the "black stain" phenomenon caused by the adhesion and stabilization of dirt components in the environment.

(Examples 1 to 7) and (Comparative Examples 1 to 3) Painted test plates to be used were prepared as follows; Solvent degreased 70
X 150mm tin plate was coated with the product name ``Olga G65 Criscle White'' (manufactured by Nippon Paint@), whose viscosity was adjusted to 22 seconds/Fort Cup #4 (20℃) as an automotive topcoat paint, and 140 mm ℃3
The bake was processed for 0 minutes.

Seven coating compositions according to the present invention in Examples 1 to 7 and three comparative coating compositions in Comparative Examples 1 to 3 were mixed with the resins and surfactants shown in Table 1 in the blending ratios (wt%) shown in Table 2. ) using a suitable mixer and mixing thoroughly.

The various coating compositions thus prepared were applied in a circular shape with a diameter of 30 to 4 Qmm at the center of each of the above-prepared test plates for evaluation. The evaluation is based on the dL value (∆) after each coating test was exposed at an outdoor exposure site at Hiyori Jidosha ■ in Yokosuka City, Kanagawa Prefecture, and visually checked and by a color difference meter < 8M color computer (manufactured by Suga Test Instruments ■)). The value is the difference in brightness between the initial stage and the time, which is most suitable for numerically determining "black stains"), and the specular reflectance was investigated. These evaluation results are shown in the lower part of Table 2.

Table 1 From Table 2 below, it can be seen that the evaluation results are poor when the blending amounts of the resin component, kerosene, and nonionic surfactant are outside the range of the present invention.

Claims (1)

[Claims] 1. A paint composition for partial repair characterized by containing a film-forming resin component and 30 to 150% by weight of kerosene based on 100% by weight of solid content of the resin component.